Partial breast irradiation versus whole breast irradiation after breast-conserving surgery in early-stage breast cancer: a systematic review.

Summary

Across 15 low-risk-of-bias randomized trials, partial breast irradiation achieved oncologic control comparable to whole-breast irradiation while reducing treatment burden and improving quality of life in appropriately selected patients. Outcomes were technique- and fractionation-dependent; notably, twice-daily 3D-CRT PBI in RAPID yielded worse acute/late toxicity and cosmesis, underscoring the need for optimized delivery and patient selection.

Key Findings

• PBI provided oncologic outcomes comparable to WBI in low-risk-of-bias RCTs.
• PBI reduced treatment burden and improved quality of life in selected patients.
• Technique and fractionation influenced outcomes; the RAPID trial reported higher toxicity and worse cosmesis with twice-daily 3D-CRT PBI.

Clinical Implications

For suitable early-stage patients, consider PBI to reduce toxicity and treatment time while maintaining control; avoid twice-daily 3D-CRT PBI protocols associated with worse cosmesis. Incorporate patient selection criteria and technique optimization into radiotherapy planning.

Limitations

• Heterogeneity across techniques and fractionation schedules limits generalizability.
• Not all trials provide long-term (>10-year) cosmesis and fibrosis data.
• Narrative synthesis without explicit pooled meta-analysis.

Future Directions

Head-to-head evaluations of optimized PBI techniques with standardized cosmesis and PRO endpoints, and long-term toxicity/fibrosis tracking; development of selection algorithms integrating clinicopathologic factors.